It almost looks like it's curdling.
Myself and my mother have a very strange coffee making problem we were hoping someone could help with. We use a very simple Baby Gagia at home, but ive been making decent flat whites on it for years. Suddenly weve been having a wierd and disgusting milk speration problem, occuring with about 80 percent of the coffees im making. Ive tried different coffees, milks, different waters (including bottled), and we have thoughouly descaled the machine. Yet it is still happening.
Basically the coffee starts out looking ok, but within minutes the froth hardens up and starts to seperate and the milk in the coffee starts to seperate. If you stir it around and leave it a few more minutes it looks like the picture attached.. tasty!
What is going on?! Feel like ive tested every variable, but its still happening!
Thanks for your help
It almost looks like it's curdling.
Highly acidic coffee can do that, especially with milk that's near the end of its drinkable life.
Java "Curds and whey anyone?" phile
Toys! I must have new toys!!!
Curdled... What milk are you using and how old is it?
What happens if you steam some milk and leave it without pouring it into the coffee? Same deal?
Any chance that some of your descaling solution is getting in to the milk?
I mean I get small bubbles in the crema from acidic beans, or from pours that I pull up short, but that looks like a biological experiment.
To me that comes down to one or more of three issues (not counting Javaphiles old / stale milk, as I assume you have that one covered). In my best order of guessing:
1) If you do not whirlpool the milk (look it up in a frothing thread somewhere), when we have the dreaded 3 week "change of season" (which just finished in WA) a lot of different cow milks curdle almost instantly when you try to froth them. Try to set up a whirlpool as rapidly as you can and see if it helps. Oh, by "almost instantly", the process takes a while but the damage is within the first second or two. Sounds familiar?
2) Descaling often does not clean severely clogged steam wands properly. I was severely CS flamed for posting one extreme I went to via a solvent based attempt (successful) in removing the gunk, however an ultrasound bath may help in all but the most stubborn cases. Unless you have access to a medical probe, all I can suggest is to check whether the steam flow is "correct for your machine" and nothing nasty is in the steam (i.e. spare descaler or milk gunk). If there is a problem, I usually find it is faster to take the wand out and drop it in a solvent (... hearing the CS flamethrowers firing up) and use pipecleaners or suchlike until it is actually clean.
3) Your milk thermometer is now out of calibration and is under reading by 5+ degrees. Check it by trying another one. Or, if you are not using a thermo, buy one (circa $15).
Hope this gives you a starting point.
Last edited by TampIt; 3rd November 2013 at 11:45 PM.
Glad I finished my coffee before I saw that picture.
You said you've tried different milks - across what range? i.e. different brands? different bottles of the same brand? Maybe try getting something completely different? You could try getting full cream powdered milk from Coles or Aldi's (I presume Woollies has it too but haven't bought from there) and make some up - not suggesting you convert over but it WILL give you consistent milk that I've never had curdle on me and I've been using it for years. Basically 1 cup per litre - I use maybe 1/4 cup more for extra creamy.
I've seen soy milk look like that after steaming - I think the guy made it too hot.
Where do you live? Could there be supply issues with the milk?
Thanks for the feedback everyone. Unfortunately still no solution. Made one coffee yesterday which wad fine, made another with all the same ingredients amd it went bad. Mind boggling.
Tried 3 different coffees now, bunch of different milk including long life lactose free. The milk doesnt seperate by itself, only once it hits the espresso shot.
I dont use a thermo, never had to to produce a fine coffee before this all started.
Havnt put the wand in solvent but gave it a good clean inside and steam flow seems perfectly stong and even to me.
Powdered milk might be worth a shot.
Its got to be something with the milk or milk preparation, if i make a shot of espresso and add warm microwaved milk never a seperation problem.
It is probably the change of season thing. Affects all milks for three weeks at the "cow end". The supply chain often takes longer. It usually only breaks down like that if it is hit with overly hot steam, only it always has a delayed reaction. The acid in the coffee tips it over the edge.
Recognising you have already cleaned your machine out, I reckon your options are
1) Use the mw for the next week or two and try again
2) Use a milk thermo (if you ever want "true microfoam" you will need one anyway) to ensure you are not overheating the milk. At the change of season it can be hairtrigger between froth & lumps.
3) If the Baby Gaggia has a removeable steam nozzle (a lot of machines do), remove it and see how clean it is inside. Zero tolerance of wand crud at this time of year.
4) Swap the steam nozzle (if possible). I ran into a nozzle once (long ago) where it suddenly & mysteriously failed. All attempts of "nozzle CPR" failed and the replacement one worked as well as the old one did originally. Go figure? I never did.
Hope you can nail the SOB
just wondering if you have a dish washing machine?
did a quick google and came up with a post on whirlpool that mentioned a guy had issues with curdling milk after he changed the rinse aid in his dish washer...
Good thought okitoki. It can affect things particularly with glass. Glass isn't a solid and is one of the strongest known substances... except for the micro-cracks that happen the instant it's exposed to air as it cools. Those cracks are the reason why you should never wash a beer glass in detergent and why pubs have special cleaner for their glass washers. The detergent gets into the cracks and then kills the head on the beer.
Maybe see if the milk thing happens in glazed china? (i.e. quality cups)
I had a laugh... could be...
but then, could be the dishwasher's rinsing cycle is not as good as it was before and left some detergent/chemical on dishes (glass and cups)...
easiest way is to confirm if dishwasher is involved, and if can wash glass/jugs differently (instead of dishwasher) to see if it causes any more curdling?
Well for now I seem to have fixed the problem by just making less hot coffees than I usually do..so luke warm .
Seems whatever causes this reaction problem is catalysed by hi temp milk..
So for now its fixed, even tho i hate luke warm coffee.. might wait a few weeks and see if the milk season changes
Gonna experiment with the rinse aid idea now.
For the person that asked, yes this was happening before the descale.
Geeeeze.. I'd love a coffee right now..
Can you think of anything that might have changed when this started happening? Of the ones that don't curdle, is it always the first one? If so, it might suggest the thermoblock of the Gaggia Baby is overheating (faulty thermostat??).Made one coffee yesterday which wad fine, made another with all the same ingredients amd it went bad. Mind boggling.
1. Does the milk separate if you make the coffee in a ceramic cup?
If not, this would suggest the rinse aid problem that Okitoiki mentioned
2. Does the milk separate if you just pour into a glass without any coffee in it? (similar to what Dragunov asked in post 4 but you didn't answer)
If you are using a stainless jug for steaming, the milk is usually hot enough if you can hold the palm of your hand against the bottom of the jug for 3 seconds before it feels too hot.
I think posting a video will help all us "other CS'rs" to work it out.
FWIW, I now think something is amiss with your machine, so I strongly recommend you try a different one. Even a $150 Breville can do a better job that you are currently managing, so I am sure you must be able to access something somewhere at or above that level.
"Geeeeze.. I'd love a coffee right now..": I feel your pain, like probably every other CS: been there, done that, never want to do it again.
Hope it sorts soon.
I have noticed that the milk I have bought in the past few weeks has been noticeably less sweet (almost bordering on sour to my tastes). I have noticed it in bought coffees in years gone by also. Most noticable in milkier coffees. Luckily I have had no problems with curdling recently; although on the one occasion I did, the dairy put it down to possible problems in the cold supply chain. So that could be another contributing factor?
I don't think it will have the same effect on a metallic surface though.
Just a thought.... are you purchasing your milk from the same shop?
I have bought milk at my local IGA that still had 3 days until expiry and no sign of being off when cold but it curdled in the jug on steaming (still didn't smell when hot).
I also know that a few years ago another IGA near to us used to turn off their fridges at night to save power!!! If you are getting it at the same shop then perhaps their fridges aren't doing their job or it's sitting out on delivery?
Rinse-aid goes into the water, it doesn't coat the dishes - it encourages the rinsing water to form sheets rather than droplets and come off the dishes. Something would be wrong if residue was remaining on the dishes (you're right about certain plastics, they don't like it at all, or the harsh dishwasher detergents). It's a shame you don't have a second machine to try to nail down whether it's being caused by a contaminant in the coffee or in the milk/steam wand.
Certainly looks and sounds like curdling. As far as I know milk will curdle when acid levels are high and the rate of change will increase with increasing temperature. Most milk is standardised, which means the milk is filtered and or separated and put back together to obtain a standard ratio of fat and protein etc so you might not see much change across brands unless you pickup milk from one of the smaller suppliers that do not standardise (Gippy milk is one I can think of). This time of year in Australia we are just coming off the traditional Melbourne Cup day milk volume peak so milk is turning over very fast which I would think reduces the risk of off (high acid) milk getting through the supply chain but on the flip side a small disruption in the milk supply can cause a long backlog.
The fact that you get the problem across several milk brands including powder makes me think that the problem is elsewhere and you have also tried several types of beans. I am thinking the water (just to give you another tangent to explore).The pH levels also vary in the water supply but I can see that you have tried bottled water already. I can only think that you are getting increased acidity through your system or steam. Maybe try replacing all the water in your boiler with bottled water.
Thx for the input everyone.
Today I tested the rinse aid option by using some brand new glasses which hadnt gone through the machine. Problem still happened. However only with the ordinary milk, the second coffee I made with longlife lactose free was ok, which suprised me because this has curdled before. Maybe just coincidence.
In answer to a previous question, no the milk doesnt curdle when left by itself. Only once it hits the coffee..and it seems to be the foam which hardens then starts coagulating.
Havnt tried powdered milk yet.
I know it's been mentioned, but perhaps you've got some descaler in the boiler? What happens if you pour the milk into a shot of water from the group (instead of coffee)?
Looks like curdling..
As a matter of interest Heks, have you flushed the boiler with fresh water a couple of time, does fresh water run through the group and allowed to cool taste like clean fresh water?
[QUit TE=oble89;514850]Like MrJack, I'm suspecting it's the water from your machine's boiler. Alternatively if you don't want to waste any more milk for the milk in water test, find a pH test strip and test the pH of the water from the grouphead.[/QUOTE]
Yeh ive ordered some litmus paper. But the milk doesnt seperate if I steam it and then put it in a shot of water. Only if its in a shot of coffee. And ive tried qbout 4 different coffees now, both fresh grinds and supermarket.
Flushed the machine again thoroughly with bottled water, still no dice..
Tho I made 2 coffees yesterday which were fine, then today they were bad again..what a tease.
Is it possible this kind of problem be caused by some "tuning" problem with the machine? I feel like ive explored all possible chemical variables.
I still think it is likely acid in your boiler water. Did a quick google, and would like to present my hypothesis
According to http://www.itisacqui.it/sitob/formagette/curdling.htm the micelles (small droplets of oil/fat with an outer layer of protein, suspended in water) become unstable at a pH around 4.6. When this happens, the protein molecules are attracted to, and get entangled in, each other (i.e.becoming curd).
I suspect your have water with a low pH, but not quite as low as 4.6. The addition of coffee, tips the pH over the edge, and curdling results. Its also possible that other molecules also play a part. Micelle stability is also related to concentration and temperature, so its possible that these factors come into play also.
You could probably investigate by performing a 'titration' with steamed milk and slowly adding (dropwise) some espresso.
Years back, I worked for a company with an full auto machine (Saeco?) and one morning I went to get my coffee and when I tasted it, it was strange. I sat it down while getting some water to rinse my mouth and when I got back it was curdled.
Turns out the guy who had run the descale process hadn't rinsed the system and walked away from it. I was off my face for a couple of hours from the cleaner.
From that day on, I looked after the machine, including putting up a sign while the process was running with POISON in extra large letters. (budding CS'er even back then apparently )
@Heks12 - you didn't answer Yelta's Q about whether you have thoroughly rinsed your machine with water... Did you try that?
Arghh..not a good story!Originally Posted by JourneymIn;I14932
Yeh I answered that Q this morning - I did flush it thoroughly with bottled and am only using bottled, but its still happening. Thats why I dont think its the water but perhaps something in the machine thats turning the water bad. Ive made over 20 coffees since it was last descaled I struggle to beleive that any acidic residue could possibly be remaining.
Ph strips and a high quality espresso machine descaler arriving this week, hopefully this will come to an end.
Thx for everyones input so far.
Oops... didn't see that line. My bad.
How did you descale? Could it be possible a chunk of a descale tablet broke away and is sitting in a pipe somewhere? Has the performance of your machine altered in any way? (slower to pour a shot, steam different, only one side of the showerscreen releasing water etc.)
As per my post #14, was this happening before you descaled the machine?
Have you tried warming a cup of milk in a microwave (or on stove top), then adding espresso from your machine?
No problem occurrrd adding microwaved milk.. my theory being because there is no foam.. as i was saying ear
Ier its the foam that seperates and curdles into the coffee. I can use the steamer and as long as there is absoluety no foam itll often be ok too.
From here on I'm just gonna sit and watch (this thread) interested in the eventual solution.
Steaming the milk will add water which could affect the stability of the micelles by changing the concentration (Google critical micelle concentration & Krafft temperature).
Also, foam is a different type of colloid, which is likely less stable than the milk.
So it's plausible that what you are experiencing is not because of something 'wrong' with your steamed milk, but just that the steamed milk is by its nature, less stable.
Keen to see what pH it comes to. You got blue litmus, right?
When I'm in a café I have long macchiatos. Some places stain the coffee with the milk and then add a dollop of froth (I have no idea why) and even after stirring in the sugar, the froth is still there. It has been heated past the point where it will mix with the coffee. My wife calls the stuff 'porn froth' as when I did the course, the instructor explained that was how cafés made capps back in the 70's, and now we should be trying to NOT make 70's froth. She promptly dubbed it porn froth.
Could you make a video of your process or even just post some pics of what your finished product looks like? ( before you add it to the coffee...)
Journeyman, didn't your wife write 50 Shades of Grey or something like that? Better keep the video in AO section of the site.
Aluminium sulfate is used to purify water.
Aluminium sulfate is used to curdle milk.
Just a thought but you could spend 1/2 a day completely purging your machine, fill it with tap water and see what happens.
Maybe something, maybe nothing.
The books suggestions was for her to write '50 Shades of Pain' as the story of my travails with my EM0480 grinder. And I was suggesting the OP make a video, so if he wants to include porn froth, I think that would be his choice.
LLLaaadddiiieees and Ggggeeennnttttllleemen, its the moment youve been waiting for...
The problem has been solved!
How? A fresh descale using a new brand of descaler. The only solution we can draw is that the previous descaler, despite being one supposedly good in coffee machine must have caused the problem. It was a dissolvable descaler, as opposed to the new one, specifically dedigned for coffee machines which comes in a liquid form.
Our only guess was that the machine must have contained a significant amount of the original descaler, as many of you suggested.
The funny thing is that I did a test pouring steamed milk into a shot of water containing that descaler and I had to put in a disturbing concentration before the same curdling occured...so I dont want to think about what I was drinking out of that machine. Goodness knows how it managed to stay in the machine through so many coffees and flushings but the new descaler has fixed the issue instantly.
Thanks so much for everyones help and persistence, damn its great to have coffee back!!
Let me be the first to congratulate you on sorting the problem out Heks.
On the other hand I cant believe the problem has taken 45 posts and 2 weeks to sort out, Barry O'Speedwagon nailed it in post 5, contaminated water in the boiler was the obvious answer.
What is worrying is the fact that inexperienced people are using descale chemicals without the knowledge to safely carry out the process, the only clue here that the water in the boiler was contaminated is the addition of milk which immediately curdled, assuming only shots or long black was being consumed there is a strong chance this stuff could have been ingested, not sure how toxic the stuff is, however I certainly wouldn't want to drink it.
Chris at Talk Coffee is correct, if you don't know how to do the job pay someone who does.
Last edited by Yelta; 24th November 2013 at 11:17 AM.
I'd be interested to know what the original descaler was and how you could miss the taste. The descaler I use is citric acid based and tastes like.....citric acid.